Such pressure roller units are used in rotary presses which comprise a frame, a rotor with drive, upper and lower rockers, which guide upper and lower pressure rollers, a frame housing, corner connections, and a cover plate. The forces occurring during the pressing process are directly introduced into the cover plate and the frame via the punches and the rockers and induce vibrations in these membrane-like components due to the pressing forces. These vibrations lead to considerable noise emissions.
A pressure roller unit of this type has been known from U.S. Pat. No. 3,891,375. In this pressure roller unit, the frame comprises upper and lower crossbeams, which are connected by vertical braces, and two columns arranged between these, on which the bearing blocks of the pressure rollers are slidable. The frame is mounted pivotably around a vertical axis in the press frame and forms a part of the press housing in the closed position. The frame may be pivoted by about 90.degree. from a working position into the open position, in which case the drive of the pressure rollers is uncoupled and the pressure rollers are disengaged from the upper and lower punches. The bearing block for the upper pressure roller is connected to the upper crossbeam by means of an adjustable spacer. The spacer is used to set the depth of penetration of the upper punches into the dies of the die disk. The bearing block for the lower pressure roller is connected via a shaft to a hydraulic adjusting unit, which acts on the lower pressure roller for the purpose of setting the tablet thickness. The drawback is that the pressing force passes over the press frame and that the mounting of the bearing blocks for the pressure rollers at the two vertical columns and at the frame pivotable in the press frame is soft and elastic, so that the prior-art pressure roller unit can be used for weak pressing forces only.